Fiber disintegrating and classifying apparatus



March 21, 1967 J, PERKINS ETAL 3,310,242

FIBER DISINTEGRATING AND CLASSIFYING APPARATUS Filed Feb. 24, 1964 United States Patent 3,310,242 FIBER DISINTEGRATING AND CLASSIFYIN-G APPARATUS Joseph K. Perkins, Amherst, and Edmund C. Chulatla, Windham, N.H., assignors to Improved Machinery Inc., Nashua, N.H., a corporation of Maine Filed Feb. 24, 1964, Ser. No. 346,884 Claims. (Cl. 241-92) This invention relates to apparatus for disintegrating and classifying fibrous materials in liquid suspensions.

In the processing of pulp for making paper, the stock is first suspended in a liquid and then must be reduced to a fine pulp in order to obtain a fine finished product. The pulp fibers must be separated and any deleterious impurities such as mineral matter removed. Although various devices have been devised in the past to accomplish either the disintegration of such fibrous materials or the classification of such materials as accepts or rejects, there have heretofore been no simple and elficient means for accomplishing both of these functions in a single simple operation.

It is therefore the prime object of this invention to provide apparatus which, in a single operating step, will disintegrate and classify such fibrous materials.

It is a further object of this invention to provide apparatus of the type described which operates in a continuous cycle.

Basically the apparatus of the present invention comprises a vertically positioned tubular chamber having a tangentially arranged accepts discharge at the upper end thereof and, rejects discharge means at the lower end thereof. Inlet means for continuously feeding a stream of fiber-liquid suspension are provided at the lower end of the chamber and are arranged to direct the stream upwardly within the chamber. Adjacent the accepts discharge is an axially positioned centrifugal pump for continuously withdrawing the pulp-liquid suspension from the chamber. Extending across the pump opening is positioned a rotatable screen adapted for rapiil rotary movement preferably attached to the centrifugal pump for rotation therewith. In this apparatus there is no structural component positioned between the inlet opening and the rotatable screen.

Other features, objects, and advantages of this invention will be apparent to those skilled in the art from the following detailed description of a preferred embodiment thereof, together with the accompanying drawings, wherein:

FIG. 1 is a sectional side elevation of a preferred embodiment of the present invention;

FIG. 2 is a cross-sectional view of the apparatus in FIG. 1 taken along the line 2-2 thereof; and

FIG. 3 is a cross-sectional view of the apparatus in FIG. 1 taken along the line 3-3 thereof.

Having reference now to the drawings and more particularly to FIGS. 1 and 3 thereof, an elongated tubular chamber of circular cross-section is provided with its axis in a substantially vertical position. Preferably, the upper portion 12 of the chamber is cylindrical and the lower portion 14 thereof is an inverted frusto-conical sec tion. Extending into the chamber at its lower portion 14 is inlet means 16 having an upwardly directed inlet opening 18 which is preferably axially positioned within said chamber. At the uppermost portion of the chamber is an accepts discharge opening 24 which is tangentially arranged with the chamber. At the lower end of the chamber positioned below the inlet means 16, are rejects discharge means generally designated by the numeral 22. Basically, the rejects discharge means 22 comprises a portion of the lower end of the chamber having axially spaced valve means 24, 26, liquid inlet means 30, a covered viewing slot 28, and an air vent 32.

Centrifugal pump means 34 are positioned at the upper end of the chamber 12, adjacent the accepts discharge 20, for continuously pumping the treated pulp-liquid suspension from the chamber through the accepts discharge. The centrifugal pump means 34 comprises a radially ex tending disk 36 carrying on its lower side a plurality of vanes 38 disposed edgewise in an annular space, as is most clearly shown in FIGS. 1 and 2. The centrifugal pump means extends substantially across the entire diameter of the chamber and .is limited at its outer extent by a chamber abutting annular wall 40, which is carried on the lower portion of the vanes 38 and has an axially extending dimension less than that of the vanes thus defining pump inlet and outlet openings, respectively n-umbered 42 and 44, the pump outlet 44 lying in a plane with the accepts discharge 20. The centrifugal pump means 34 are connected to axially positioned drive means 46 which extend through the upper portion of the chamber where it may be connected to suitable power source at 48.

A rotatable perforated screen means 50 are provided to cover the pump inlet opening. Preferably the screen is attached to the centrifugal pump means 34 for simultaneous rotation therewith as said drive means is operated. Preferably, stationary scraper means 52, mounted on the uppermost portion of the chamber, are also provided immediately below the screen means, said scraper means having a surface in intimate contact with the screen means.

In the chamber thus described, no structural component of the chamber is interposed between the inlet means and the screen means.

In operation rejects valve 26 is first closed and rejects valve 24 opened. Fiber-liquid suspension is then introduced through inlet opening 13 into the interior of the chamber. The centrifugal pump means 34 and screen means 50 are operated in rotary fashion. As the fiberliquid suspension moves upward from the inlet opening to the screen, it is forced into a spiral path by the rotary motion of the screen and pump. As the fibrous material contacts the surface of the screen, the shear forces of the screen, which is preferably rotated at a speed of approximately 600 to 700 r.p.m., defibers the stock and a portion of the suspension, thus treated, passes through the screen into the pump opening 42 through the pump outlet 44 and out of the accepts discharge 20. Material which istoo large to pass through the screen and rejects material of high specific gravity is forced into a spiral path near the outside of the chamber wall. At this point separation occurs as centrifugal forces move heavier particles into a path more remote from the axis than that of the lighter materials. The heavier particles then move downward toward the rejects discharge and are collected there. The lighter stock is recirculated and ultimately, if acceptable, passes through the screen and through the accepts discharge. The collected heavier particles are observed through a slot 28 and when a substantial amount of material has been collected, upper rejects valve 24 is closed and the lower valve then opened. When the rejects material has been removed from the chamber, the lower valve is closed, but before the upper valve is reopened, liquid is fed into the rejects discharge chamber 22 through inlet 30. Air is simultaneously exhausted from the chamber through opening 32. When the rejects discharge chamber is filled with liquid, the upper valve is reopened and rejects continue to be collected at that point.

This invention, thus, provides a highly efficient means for continuously disintegrating or defibering and cleaning pulp stock. It will be understood by those skilled in the art that the description of a single preferred embodiment 3 of this invention is not intended to limit the scope of the appended claims.

What is claimed is: 1. Apparatus for disintegrating and classifying fibrous materials in a liquid suspension, comprising:

a tubular chamber having its axis vertically positioned; an accepts discharge port at the upper portion of said chamber; a rejects discharge means axially positioned at the lower portion of said chamber; an inlet means extending into the lower portion of said chamber and extending upwardly within said chamber along the axis thereof, said inlet means having an upwardly directed, axially positioned inlet opening within said chamber for continuously introducing and directing a stream of said fiber-liquid suspension under pressure toward the upper end of said chamber; centrifugal pump means axially positioned within said chamber at the upper portion thereof, for continuously pumping said suspension from said chamber into said accepts discharge port, said pump means having a pump inlet intermediate said inlet means and said accepts discharge port; rotatable screen means extending across said pump inlet; said rotatable screen means being limited to containing apertures of a predetermined size which can pass liquid and particles of a smaller size while particles of a larger size are rejected and thrown radially outwardly by said screen means; drive means for driving said pump means and said screen means; and said screen means being spaced from said inlet means sufiiciently to create a recirculating type of flow between said screen means and said .inlet means whereby particles rejected by the screen means can flow outwardly and downwardly with the lighter particles in said downward flow being recirculated into the stream flowing from said inlet means toward said screen means and the heavier particles flowing downward below the inlet means to the rejects discharge means.

2. The apparatus of claim 1 wherein:

said pump means has a pump outlet opening in a plane with said accepts discharge port.

3. The apparatus of claim 1 wherein:

said chamber is cylindrical at its upper end and conical at its lower end.

4. The apparatus of claim 1 wherein:

said screen means is attached to said pump means at said pump inlet for rotation with the pump means by said drive means.

5. The apparatus of claim 1 including:

stationary scraper means mounted adjacent the lower face of said rotatable screen means for cleaning said screen means.

References Cited by the Examiner UNITED STATES PATENTS 1,037,659 9/1912 Rembert 230127 1,420,665 6/1922 Newcornbe 408 2,496,359 2/1950 Ryrnarm 24l46 3,128,051 4/1964 Smith 24l46 3,234,716 2/1966 Sevin 2l0297 X WILLIAM W. DYER, JR., Primary Examiner.

H. F. PEPPER, Examiner. 

1. APPARATUS FOR DISINTEGRATING AND CLASSIFYING FIBROUS MATERIALS IN A LIQUID SUSPENSION, COMPRISING: A TUBULAR CHAMBER HAVING ITS AXIS VERTICALLY POSITIONED; AN ACCEPTS DISCHARGE PORT AT THE UPPER PORTION OF SAID CHAMBER; A REJECTS DISCHARGE MEANS AXIALLY POSITIONED AT THE LOWER PORTION OF SAID CHAMBER; AN INLET MEANS EXTENDING INTO THE LOWER PORTION OF SAID CHAMBER AND EXTENDING UPWARDLY WITHIN SAID CHAMBER ALONG THE AXIS THEREOF, SAID INLET MEANS HAVING AN UPWARDLY DIRECTED, AXIALLY POSITIONED INLET OPENING WITHIN SAID CHAMBER FOR CONTINUOUSLY INTRODUCING AND DIRECTING A STREAM OF SAID FIBER-LIQUID SUSPENSION UNDER PRESSURE TOWARD THE UPPER END OF SAID CHAMBER; CENTRIFUGAL PUMP MEANS AXIALLY POSITIONED WITHIN SAID CHAMBER AT THE UPPER PORTION THEREOF, FOR CONTINUOUSLY PUMPING SAID SUSPENSION FROM SAID CHAMBER INTO SAID ACCEPTS DISCHARGE PORT, SAID PUMP MEANS HAVING A PUMP INLET INTERMEDIATE SAID INLET MEANS AND SAID ACCEPTS DISCHARGE PORT; ROTATABLE SCREEN MEANS EXTENDING ACROSS SAID PUMP INLET; SAID ROTATABLE SCREEN MEANS BEING LIMITED TO CONTAINING APERTURES OF A PREDETERMINED SIZE WHICH CAN PASS LIQUID AND PARTICLES OF A SMALLER SIZE WHILE PARTICLES OF A LARGER SIZE ARE REJECTED AND THROWN RADIALLY OUTWARDLY BY SAID SCREEN MEANS; DRIVE MEANS FOR DRIVING SAID PUMP MEANS AND SAID SCREEN MEANS; AND SAID SCREEN MEANS BEING SPACED FROM SAID INLET MEANS SUFFICIENTLY TO CREATE A RECIRCULATING TYPE OF FLOW BETWEEN SAID SCREEN MEANS AND SAID INLET MEANS WHEREBY PARTICLES REJECTED BY THE SCREEN MEANS CAN FLOW OUTWARDLY AND DOWNWARDLY WITH THE LIGHTER PARTICLES IN SAID DOWNWARD FLOW BEING RECIRCULATED INTO THE STREAM FLOWING FROM SAID INLET MEANS TOWARD SAID SCREEN MEANS AND THE HEAVIER PARTICLES FLOWING DOWNWARD BELOW THE INLET MEANS TO THE REJECTS DISCHARGE MEANS. 